638 
ME. W. K. PAEKEE ON THE STEUCTUEE AND 
into the pedicle, beneath the annulus. Above (fig. 2, a.t., jpd., q.), that large cartilaginous 
crescent has pushed, as it were, the solid substance of the mandibular pier before it, as 
though it had been so much dough. The one has taken a visible impression of the 
other. 
Beneath the elbow the condyle for the hyoid (fig. 3) has become faint, for that bar 
(fig. 4', c.hy .) is loosening its attachment there. Over that, part of the orbitar process 
(or.]).) has been reduced to a sigmoid style, overlapping the angle of the pier. 
The pterygo-palatine is no longer an extensive isthmus merely, which keeps the 
quadrate very close to the ethmoid ; but added to that conjugational part is a retreat- 
ing band, wide at first, but still steadily widening backwards, until it passes externally 
into the quadrate angle, and internally into the pedicle ('pd., q.). This newly developed 
tract is the pterygoid; for in the last stage the whole of the pterygo-palatine was 
merely an “ ethmo-palatine,” like a secondary conjugational band. A little crest of car- 
tilage marks the point where the postpalatine passes into the pterygoid, and in front 
a prepalatine knob has appeared, which, below (fig. 3), has a thickened, condyloid 
appearance. 
As a correlate of this retreat of the quadrate angle and trochlear facet, the mandible 
has grown largely (Plate 58. fig. 4, ar., mlc.), for the mouth is no longer Siluroid, but has 
become Batrachian. The whole arch is an elegant half-hoop ; the articular end is very 
thick ; and a uniform condyle projects from its upper surface, answering to the neat 
scooping on the angle of the quadrate. At the end of each Meckelian rod is the 
“inferior labial” (l.l .) ; and this, with its fellow, is more than ever in a line with the 
mandible itself. These labials help to form the “ mentum ; ” they do not degenerate 
into fibrous tissue, or coalesce with the ventral end of the mandible, but become the 
“ mento-Meckelian ” element, in most Batrachia. But the adult shows no signs of 
them (fig. 6), nor has it any “ mento-Meckelian ” bone. In front of the mandible there 
is a small dentary, and below and within it a large ectosteal articulare (d., ar.). 
Notwithstanding that the stapes has been solid cartilage for the three last stages, 
there is, to me, no appearance of a chondrified columella, although I have sought for it 
with great care (Plate 57. figs. 2 & 4, and Plate 58. figs. 2, 3, st.). 
And although the legs are large and strong, yet certain parts are but little metamor- 
phosed at present. Thus the hyoid cornua (fig. 4. c.hy.) are now at their largest growth, 
although loosening themselves from their mandibular swinging point. What changes 
await these bars may be seen by comparing them in this fourth stage with those of the 
adult (fig. 5, c.hy.). They never reach higher towards the auditory sac than their 
counterparts in the “ Urodela ; ” this is another peculiarity of this aglossal type. The 
basi-hyobranchial bar ( b.hy ., b.br.) still retains its perfectly larval condition. 
The auditory capsules, with their outgrowths, are mainly cartilaginous above (fig. 2), 
nearly the whole of the exquisite canals of the labyrinth being visible through the clear 
walls ; they have ruled the outer form of the capsule. But that outer form is still 
further modified by the “ awning,” which is stretched out from their antero-external 
